RESEARCH AND EDUCATION
Evaluating ceramic crown margins with digital radiography William Maxwell Wahle, DDS, MS,a Radi Masri, BDS, MS, PhD,b Carl Driscoll, DMD,c and Elaine Romberg, PhDd Good marginal adaptation and ABSTRACT adequate strength are the Statement of problem. Radiographs aid in clinically determining crown fit, specifically interproxmost important characteristics imal margins where tactile and visual methods may be limited. However, investigations of the utility for the long-term success of of digital radiographs as a tool for evaluating the marginal openings of ceramic crowns are lacking. complete coverage restoraPurpose. The purpose of this in vitro study was to assess whether marginal adaptation for ceramic tions.1 Marginal adaptation is crowns and for metaleceramic crowns with a metal collar can be identified with digital radiographs. essential for the prevention of Material and methods. One lithium disilicate crown, 1 fluorapatite crown, and 1 metaleceramic microleakage.2-13 The larger crown were fabricated for a maxillary premolar. The crowns were attached to a custom-designed the marginal discrepancy, the device that allowed the marginal discrepancy to be changed. A total of 10 increments were more the luting agent and measured starting at 0 to 20 mm and increasing every 20 mm to a maximum opening of 180 to dentin are exposed to the oral 200 mm. At each increment, 2 radiographs were made of the crowns, using a digital sensor, 1 environment, increasing the perpendicular to and 1 at 80 degrees to the long axis of the tooth. To test whether digital radiographs could be used to accurately identify “acceptable” and “unacceptable” margins, 21 risk of seal failure and secdentists were asked to rate the radiographs as “acceptable” or “unacceptable.” The chi square ondary caries due to bacterial test was used to analyze differences between the dentists’ evaluations and the actual marginal infiltration.14 Improper fit can opening (a=.05). For the purposes of this study, a marginal discrepancy greater than 80 mm was affect the fracture strength of considered “unacceptable.” silica-based ceramic crowns, Results. Of all marginal discrepancies exceeding 80 mm, 78.6% of the metaleceramic crown reducing the strength and radiographs were incorrectly scored as “acceptable” (P
Evaluating ceramic crown margins with digital radiography William Maxwell Wahle, DDS, MS,a Radi Masri, BDS, MS, PhD,b Carl Driscoll, DMD,c and Elaine Romberg, PhDd Good marginal adaptation and ABSTRACT adequate strength are the Statement of problem. Radiographs aid in clinically determining crown fit, specifically interproxmost important characteristics imal margins where tactile and visual methods may be limited. However, investigations of the utility for the long-term success of of digital radiographs as a tool for evaluating the marginal openings of ceramic crowns are lacking. complete coverage restoraPurpose. The purpose of this in vitro study was to assess whether marginal adaptation for ceramic tions.1 Marginal adaptation is crowns and for metaleceramic crowns with a metal collar can be identified with digital radiographs. essential for the prevention of Material and methods. One lithium disilicate crown, 1 fluorapatite crown, and 1 metaleceramic microleakage.2-13 The larger crown were fabricated for a maxillary premolar. The crowns were attached to a custom-designed the marginal discrepancy, the device that allowed the marginal discrepancy to be changed. A total of 10 increments were more the luting agent and measured starting at 0 to 20 mm and increasing every 20 mm to a maximum opening of 180 to dentin are exposed to the oral 200 mm. At each increment, 2 radiographs were made of the crowns, using a digital sensor, 1 environment, increasing the perpendicular to and 1 at 80 degrees to the long axis of the tooth. To test whether digital radiographs could be used to accurately identify “acceptable” and “unacceptable” margins, 21 risk of seal failure and secdentists were asked to rate the radiographs as “acceptable” or “unacceptable.” The chi square ondary caries due to bacterial test was used to analyze differences between the dentists’ evaluations and the actual marginal infiltration.14 Improper fit can opening (a=.05). For the purposes of this study, a marginal discrepancy greater than 80 mm was affect the fracture strength of considered “unacceptable.” silica-based ceramic crowns, Results. Of all marginal discrepancies exceeding 80 mm, 78.6% of the metaleceramic crown reducing the strength and radiographs were incorrectly scored as “acceptable” (P
